In recent years, while attention has strongly been paid to utilization of recycling or renewable energy, especially, attention has been paid to or focused on utilization of biomass energy as one of recycling or renewable energy.
There exist various forms in utilization of biomass energy. As one of such forms, such system as producing aqueous gasses from biomass, then for generating electric powers and further for providing heat has been proposed.
For producing aqueous gasses from biomass, first of all, carbonization of biomass is necessary. For example, a carbonizing furnace which comprises a cylindrical body and an inner cylindrical member accommodated therein is disclosed in, for example, Patent Document 1.
For producing aqueous gasses from the carbonized biomass, steps of thermal decomposition and gasification are necessary. For example, in Patent Document 2, there is disclosed a thermal decomposition gasification apparatus which is formed by an outer cylindrical member, an inner cylindrical member, a turn-table and heat-storage projection members.
As explained above, in the course of producing aqueous gasses from biomass, largely divided, two steps are needed, one for carbonization of biomass and second for thermal decomposition and gasification of the carbonized biomass. In the prior art, these steps have been performed separately by the above mentioned separate apparatuses.
However, since such conventional system requires two separate apparatuses, one for carbonization of biomass and the other for thermal decomposition and gasification of the carbonized biomass, there inevitably occurs large thermal loss. Further, it takes a considerable long time until the temperature of furnace for thermal decomposition and gasification is stabilized where the heat generated in the step of carbonizing biomass is utilized for the thermal decomposition and gasification. Furthermore, in the conventional system, it has been difficult to achieve evenness or uniformity of temperature distribution of thermal decomposition and gasification furnace.
Further, it has been desired to provide a technique for preventing the reaction residuals from adhering on the inners of the apparatus after the thermal decomposition and gasification of the carbonized biomass.